State of the art mailing machines can perform such automatic functions as handling mail of different sizes and thicknesses, envelope sealing, mail weighing, mail stamping, and mail sorting. The typical processing sequence starts at the front end of the machine where the main is stacked. The stacked mail is then registered against a reference wall of the machine and the next step in the process is to remove individual mail pieces from the bottom of the stack and thereafter process those individual mail pieces through the various modules of the machine. This process is called singulation, and the apparatus involved a singulator. Many such devices or apparatus are well known in the art, but suffer from one or more of the following shortcomings. In some instances, singulators are incapable of handling mail pieces such as envelopes of varying thickness. In other instances, the known singulators are incapable of handling flapped and unflapped mail. In still other instances, the known singulators are incapable of processing stuffed envelopes at a fast enough rate.